Field of the Invention
The present invention relates to a technique of improving an autonomous lawn mower.
Description of the Related Art
Lawn mowers include an autonomous lawn mower capable of autonomously traveling without being steered by a worker. This autonomous lawn mower can automatically travel on the lawn by traveling wheels, and mow the lawn by a cutter blade which rotates almost horizontally, and is known as a so-called robotic lawn mower.
A lawn mowing motor for driving the cutter blade is held by a motor holding member. The height of the lawn mowing motor can be adjusted by vertically moving the motor holding member with respect to a frame including the traveling wheels. Consequently, it is possible to adjust the height of the cutter blade with respect to the lawn, that is, a so-called lawn mowing height. The method of vertically moving the motor holding member includes an electrical operation method known from International Publication No. 2014/007694, and a manual operation method known from European Patent Application Publication No. 2783563.
An autonomous lawn mower known by International Publication No. 2014/007694 includes a motor holding member holding a lawn mowing motor, a rack provided on the motor holding member, a screw portion for vertically moving the motor holding member by being meshed with the rack, and a gear driving motor for driving the screw portion. The motor holding member, screw portion, and gear driving motor are attached to a frame. The rotation of the motor holding member and rack is regulated, but the vertical movement thereof is permitted. The rack vertically moves when the gear driving motor rotates the screw portion. As a consequence, the motor holding member vertically moves, so the heights of the lawn mowing motor and a cutter blade can be adjusted.
An autonomous lawn mower known by European Patent Application Publication No. 2783563 includes a motor holding member holding a lawn mowing motor, a vertical driving member for vertically moving the motor holding member, and a manual driving mechanism for manually driving the vertical driving member. The motor holding member, vertical driving member, and manual driving mechanism are attached to a frame. The rotation of the motor holding member is regulated, but the vertical movement thereof is permitted. The vertical movement of the vertical driving member is regulated, but the rotation thereof is permitted. The manual driving mechanism includes a driven gear provided in the vertical driving member, a driving gear meshed with the driven gear, and an operation knob for manually rotating the driving gear. The vertical driving member rotates when the operation knob is rotated. Consequently, the motor holding member vertically moves, so the heights of the lawn mowing motor and a cutter blade can be adjusted.
A method of vertically moving the motor holding member is appropriately set in accordance with the machine type of an autonomous lawn mower. However, an electric type vertical driving device and manual type vertical driving device are largely different in arrangement, so the number of dedicated parts of each method is large. This is disadvantageous in reducing the production cost of an autonomous lawn mower because it is necessary to produce the dedicated parts of each method.